Microwave dielectric properties of Mg_1.8R_0.2Al₄Si₅O₁₈ (R = Mg, Ca, Sr, Ba, Mn, Co, Ni, Cu, Zn) cordierite ceramics and their application for 5G microstrip patch antenna

In this work, the effects of divalent ions on the phase structure, microstructure, and microwave dielectric properties of Mg_1.8R_0.2Al₄Si₅O₁₈ (R = Mg, Ca, Sr, Ba, Mn, Co, Ni, Cu, Zn) cordierite ceramics were investigated. Complex chemical bond theory, Raman spectrum and infrared reflectance spectrum were employed to understand the relationship among structural characteristics, vibration modes and microwave dielectric properties for alkaline earth and transitional metal divalent elements doped cordierite ceramics. The optimal microwave dielectric properties were obtained for Mg_1.8Ni_0.2Al₄Si₅O₁₈ with ε_r of 4.53, Q×f of 61,880 GHz and τ_f of -32 ppm/℃. Finally, a 5G-Sub 6GHz patch antennas with a central frequency of 4.91 GHz was successfully designed and fabricated using a Mg_1.8Ni_0.2Al₄Si₅O₁₈ substrate. The antenna exhibited excellent performance with a gain of 5.83 dBi and an efficiency of 76 %, showing promise to be employed in 5 G/6G millimeter-wave communication technology.